Earlier quoted context omitted.
I didn't watch the whole thing just jumped around but he has included slides that are marked 'SECRET//NOFORN' so if that material is accurately classified at that level (and its disclosure was not authorized), well he probably shouldn't be presenting to that. Of course whether those slides would cause 'serious damage' to national security is a whole other matter or maybe it was 'authorized'.
Perhaps they were previously leaked through Snowden or others and he's only included them in his slides? Then he's not disclosing anything. He hasn't worked at NSA for a loooong time.
Classified information does not become unclassified just because it is publicly available if I remember correctly. Either way, I can't comment on whether including them in his slides is disclosing/divulging or not.